iserith
Magic Wordsmith
A Passive Perception check can be something like repeatedly searching for something, but I think it can also be actually passive, thus the name.
Darkron Is in his home and walks into a room. An assassin stands behind the door hiding. Darkron isn’t actively searching, but as a DM I’ll use his passive perception score to give whoever it was that came through the door an opportunity to notice the assassin or something strange just because their senses are so acute.
The rules say passive Perception is for what I said upthread, but also if the DM just wants an ability check that is secret. Your example looks to be the latter. But make no mistake, the character is actively aware of his or her surroundings. You're just not requiring the players to say so and working off an assumption (a common approach as noted above), and assumptions can be problematic (but not always).
I think it is the DM’s role to describe what a PC experiences — sometimes that might involve telling players what they feel and thoughts that might occur to them.
It never has to involve that except in a case of magical compulsion or the like.
To me, a feeling is not something I do. Thoughts that pop into my head are not something I have conscious control over.
What I do is react to my feelings or random thoughts.
I don’t choose to feel sad, but I can try to do things to snap out of it.
I choose to eat a sandwich that has spoiled and then feel like I want to die, but I certainly don’t choose to feel that way; that is a result of my action. I can then act to relieve that feeling somehow.
My feelings are can result directly from my actions, but sometimes they result in how external stimuli affect me whether I want that to happen or not.
This, to me, just looks like post-hoc reasoning for wanting to tell players how their characters think and feel. The DM could more easily just say nothing about it and let the players establish this as is their role.
It also looks like you're straying away from the intent of the words "feel" or "feeling" as I noted upthread which makes these discussions difficult.
I recommend challenging yourself for the next month not to tell players how their characters think or feel. Maybe ask them how their characters think or feel instead, if they don't volunteer that info themselves. Give it a shot and watch what happens. You might be surprised.